Copper lead alloys



2,996,377 COPPER LEAD ALLOYS Eugen Vaders, Pocking uber Starnberg (131)), Upper Bavaria, Germany No Drawing. Filed Aug. 3, 1959, Ser. No. 830,989 Claims priority, application Germany Feb. 19, 1953 '5 Claims. (Cl. 75-156) My invention relates to copper-lead alloys for use in making bearings and like parts with great mechanical resistance and intended to withstand friction.

This application is a continuation in part of my copending application Serial Number 408,046, filed February 3, 1954, now abandoned. Copper alloys having a high percentage of lead and being generally denoted as lead bronzes are often used for the manufacture of high-duty bearings.

While the binary lead bronzes are only usable as coating metals, i.e. in combination with a resistant steelbearing shell, the multiple or complex lead bronzes may withstand high loads without the presence of a supporting steel-bearing.

The strength and the mechanical resistance of these lead bronzes may be improved by the admixture of metals which alloy with the copper. The most frequently used metals of this type are nickel and tin. According to German DIN 1706 the presence of the tin may amount up to 10 percent and that of the nickel up to 2.5 percent.

The invention represents an important development in the above identified sense, and its progress is based on the presence of silicon in the copper-lead alloys or lead bronzes. The silicon is preferably added at a ratio of 0.1 to 6 percent. Due to its deoxidizing action comparatively small admixtures of silicon already improve the coherence between the supporting shell and the lead bronze. By the use of a greater quantity of silicon the mechanical properties of the lead bronzes are improved to a much higher degree than by the presence of an equal amount of tin.

Nevertheless the alloys according to the invention may contain from 0.1 to 10 percent of tin, whereas the lead contents are more than 5 up to 40 percent. It has been found that even with such a small amount of not more than 2 percent of tin, the 6-phase is formed. The 5- phase is of great importance with regard to the anti-fric tional properties of the alloy as is well known from the pure copper-tin alloys. Its formation is not influenced by the admixture of 0.1 to 10 percent of cadmium and 0.1 to 5 percent of aluminum, both of which may also be present. In accordance with the invention the alloys may further contain 0.1 to 5 percent of antimony or arsenic, the rest being copper. The elements aluminum, antimony and arsenic may be added singly or in suitable combination.

Copper-base alloys of silicon and lead usually contain not more than 3 percent lead, which is not sufiicient to provide an efiicient bearing alloy. Other known copper-- fired tates Patent ice tin have the tendency to segregate. .This tendency may be eliminated or, at least, greatly reduced by the admixture of the above named metals. The most important of these metals are cadmium and antimony. Experiments carried out with the alloys containing only 0.1 to 0.5 percent of antimony or 0.1 to 5 percent of cadmium have shown the great influence of these metals on the structure of the copper-lead-silicon-tin alloys of the present invention. The presence of cadmium, antimony or of both together causes a fine grain structure; moreover the fine distribution of the lead is greatly improved.

An alloy according to the invention and composed as follows:

Percent Copper 7-8.7 Silicon g 2 Lead 12 Cadmium 5 Tin 2 Aluminum 0.3

Percent Copper 86.5 Silicon 2 Lead 10 Tin l Cadmium 0.2 Aluminum 0.3

If suitably composed, these copper-silicon-lead-tin alloys are even superior to alloys with high tin content, their tensile strength is between 30 to 35 kg. per sq. mm., while with the customary copper-tin alloys a tensile strength may be obtained of only about 20 kg. per sq. mm. The elongation is approximately the same in both cases.

Furthermore the alloys may contain 0.1 to 5 percent of nickel, cobalt, iron, manganese and 0.1 to 10 percent of zinc, singly or in combination. These admixtures serve to improve the strength and the hardness of the alloys. Moreover additions of iron and manganese refine the grain.

A further alloy according to the invention has the following composition:

In this alloy iron or nickel or both together may be substituted by an equal amount of manganese.

Consequently the present invention consists not only in the provision of copper-lead alloys which are superior to those heretofore proposed, but it also includes alloys of greater hardness and improved tensile strength.v Alloys which contain one or more of the components of the group nickel, iron, manganese and zinc and have a lead In such case the tin content should not ex-- 3 content of more than to percent show the following mechanical properties.

On the other hand a well known. lead bronze containing 80 percent copper, 10 percent lead, 10 percent tin shows properties of onlyas sandcast 25. 2 12. 1 12. 5 80. 4

The composition of several alloys in conformity with the invention are given in the following table, the rest of the constituents, of course, being copper.

Si, Pb, Sn, Cd, A1, Sb, Ni, Fe, Zn, -Per- Per- Per- Per- Per- Per- Pcr- Per Percent cent cent cent cent cent cent cent cent The alloys produced in accordance with the invention and containing the claimed amount of silicon show a marked improvement with regard to fluidity when, for instance, compared with lead bronzes having only tin as their third component. In the same manner as with ordinary tin bronzes the favorable influence of the (xi-l-B eutectoid on the flow properties of the alloys prevails in the presence of silicon and tin even if only relatively small quantities of these metals are present.

The load-carrying capacity of the instant alloys, if used as bearing metals, is extremely high. It surpasses even that of the copper-tin bronzes with high tin content, which are considered at present as the most eflicient bearing metals. Furthermore, the instant alloys have excellent run-in properties and resistance to wear.

The alloys according to the invention may be improved by a heat treatment that consists of quenching the said alloys from a temperature of between 300 to 900 C, and heating the same for 1 to 30 hours to a temperature between to 500 C.

It is well known that alloys containing silicon, nickel, iron, manganese and lead can be heat-treated. But it was a surprising fact that the results of this heat treatment are not detn'mentally influenced by other components like tin, cadmium, aluminum or others according to the invention. I

Since certain changes in carrying out the above invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description be interpreted as illustrative and not in a limiting sense.

What I claim is:

l. A copper base bearing metal comprising 0.2 to 1 percent silicon, 10 to 25 percent lead, 02 to 1 percent tin, 0.1 to 1' percent cadmium, 0.3 to 0.5 percent aluminum, the rest being copper.

2. A copper base bearing metal comprising 1 to 2.5 percent silicon, -6 to 12 percent lead, 0.2 to 1 percent tin, 0.1 to 1 percent cadmium, 0.1 to 0.5 percent aluminum, the rest being copper.

3. A copper base bearing metal comprising 0.2 to 1 percent silicon, 10 to 25 percent lead, 0.2 to 5 percent tin, 0.1 to 5 percent cadmium, 0.1 to 0.5 percent aluminum, 0.1 to 1 percent antimony, the rest being copper.

4. A copper base bearing metal comprising 2.5 to 4 percent silicon, 5.5 to 8 percent lead, 0.1 to 5 percent tin, 0.1 to 2 percent cadmium, 0.1 to 1 percent aluminum, the rest being copper.

5. A copper base bearing metal comprising 1 to 2.5 percent silicon, 10 to 25 percent lead, 0.1 to 5 percent tin, 0.1 to 1 percent cadmium, 0.1 to 1 percent aluminum, 0.5 to 5 percent of at least one metal selected from a group consisting of antimony, arsenic, nickel, cobalt, manganese, iron and 0.1 to 10 percent zinc, the rest being copper.

FOREIGN PATENTS France Apr. 12, 1934 

1. A COPPER BASE BEARING METAL COMPRISING 0.2 TO 1 PERCENT SILICON, 10 TO 25 PERCENT LEAD, 0.2 TO 1 PERCENT TIN, 0.1 TO 1 PERCENT CADMIUM, 0.3 TO 0.5 PERCENT ALUMINUM, THE REST BEING COPPER. 